Q. I am working on a project where native (New York) hemlock boardand-batten siding has been specified. I am not familiar with this material. How should I prep and install it?

A. First, the hemlock should be dry — preferably at 15% or less moisture content. The boards should be spaced 1/2 inch apart, with 1 1/2-inch battens. Use stainless-steel nails, and secure the boards with one line of 8d siding nails in the center. Secure the battens with one line of 10d nails between the boards. The siding should be finished with a semitransparent or opaque oil-based penetrating stain.

Hemlock is not a great choice as a siding material. On a scale of 1 to 10, it rates as a 6 in paint retention, and about 5 in resistance to cupping. It checks conspicuously.